CSS-Tricks: Myth Busting: CSS Animations vs. JavaScript

Conclusion

Are CSS animations “bad”? Certainly not. In fact, they’re great for simple transitions between states (like rollovers) when compatibility with older browsers isn’t required. 3D transforms usually perform very well (iOS7 being a notable exception), and CSS animations can be very attractive for developers who prefer putting all of their animation and presentation logic in the CSS layer. However, JavaScript-based animation delivers far more flexibility, better workflow for complex animations and rich interactivity, and it often performs just as fast (or even faster) than CSS-based animation despite what you may have heard.